Refrigerating plate and internal reinforcement therefor



H. W. KLEIST Feb. 24, 1948.

REFRIGERATING PLATE AND INTERNAL REINFORCEMENT THEREFOR 2 Sheets-Sheet 1Filed Sept. 4, 1945 I 727/67271'07" zermajz Wl lez si' E9 PM w H. W.KLEIST Feb. 24, 1948.

REFRIGERATING PLATE AND INTERNAL REINFORCEMENT THEREFOR Filed Sept. 4,1945 2 Sheets-Sheet 2 .Afivenzov- .Herman Wjf'lezjs @454 mm emnteareb.24, 1948 REFRIGERATING PLATE AND INTERNAL REINFORCEMENT THEREFOR HermanW. Kleist, Chicago, Ill., asslgnor to Dole Refrigerating Company,

ration of Illinois Chicago, 11]., a corpo- Application September 4,1945, Serial No. 614,420 3 Claims. (Cl. 62-126) My invention relates toan improvement in refrigeration and relates particularly to thestructure of cold plates.

One purpose is to provide an improved cold plate for refrigerators andthe like- 'Another purpose is to provide an improved plate in which avariable volume of liquid is em- I illustrate the invention more or lessdiagrammatically in the accompanying drawings, wherein:

Figure 1 is a side elevation with parts in skeleton outline and partsbroken away;

Figure 2 is a section on an enlarged scale on the line 22 of Figure 1;

Figure 3 is a detail section on a still larger scale;

Figure 4 is a section on the line 44 of Figure 3; and

Figure -5 is a detail section on the line 5-5 of Figure 2. Figure 6 is avertical section on an enlarged scale of an embodiment in which but asmall amount of eutectic fluid is used.

Like parts are indicated by like symbols throughout the specificationand drawings.

Referring to the drawings A indicates generally a cold plate including acoil in circuit with a mechanical refrigeration mechanism. Themechanical refrigeration mechanism is diagrammatically shown at B. Itincludes a base i, any suitable compressor 2, driven by a motor 3through the belt 4. I diagrammatically indi-- cates any suitablecondenser coil and 6 is any suitable receiver. 1 is a high pressure ductextending from the receiver to any suitable expansion valvediagrammatically indicated as at 8. .9 is a refrigerant delivery ductextending from ,the expansion valve "liquid refrigerant, for

described evaporator structure.

8 and adapted'to deliver evaporation, to the below I0 is a low pressurereturn duct adapted to return the evaporated refrigerant to thecompressor. more specifically to the cold plate which is included in theabove mentioned cycle I employ a coil which includes a plurality ofrectangular and preferable rectilinear pipe lengths l5. These Referring;

pipe lengths may conveniently be assembled in groups of like length. Twosuch groups are shown in Figure 1 forming an upper coil C and a lowercoil D. The employment of rectilinear pipes provides a coil having flatfaces defined by parallel planes. This arrangement is ideal for use incold plates.

Referring, for examplerto Figure 2, I employ a plate having parallelswalls It and H which are sealed together at their edges, for example, bythe employment of flanges l8 on one such wall welded or otherwisesecured as at l9 to the opposite wall. The coil formed of therectangular tube lengths l5 therefore abuts against the inner faces ofthe walls It and I! with a maximum area of close contact. In formingcoils of rectangular cross section, it is not advantageous to bend thecoil. I may find it advantageous to employ preformed couplings orconnectors which may be bent or otherwise formed from tubing which'isnot rectangular in cross vsection. Referring for example to Figures 3and 4, I illustrate connectors 20 which may be bent or otherwise formedfrom tubing having a generally circular cross section, each suchconnector may terminate at each end in a single common plane as at H,.22. Such a connector may then be easily welded as at 23 to the adjacentend of an adjacent pair of rectangular rectilinear tubes l5. If anyexcess metal is provided it maybe ground'ofl or otherwise smoothed offto provide a flush surface such as is shown in Figure 4. Preferably thediameter of the connector 20 is the same as the diameter of the tubesl5, to provide a maximum contact with the inner faces of the walls l6and I1.

In the particular plate shown in Figure 1, I illustrate a connectorhaving a nipple 25 to receive the end of the refrigerant inlet 9 or ofany elbow or connector member applied thereto. One branch of theconnector 24 extends to the coil C and the other to an intermediatepassage or duct'26 which extends to the upper tube I511. of the coil D.A discharge fitting or connector 21 is employed, one arm of whichreceives the outlet duct 28 of the coil C. The nipple 30 is incommunication with any suitable fitting and is adapted to connect itwith the evaporant return duct I 0. It will be understood that anysuitable eutectic may be located within the space within the walls l6and 11. Preferably I also subject the space within the plate to avacuum. 3| indicates any suitable fitting or valve enclosure where theeutectic fluid may be admitted to the space between the walls I 6 and I!through After the eutectic fluid has been introduced I may employ thefitting 3| as a means for exhausting the air from the interior of theplate to provide a partial vacuum. The ball 3 serves as a check valveagainst the entry of atmospheric air. 35 is any suitable drainagefitting for draining the eutectic liquid from the interior of the plate.

In Fig. 2 I illustrate a form of plate the interior of which is largelyfilled by a eutectic fluid, the top level of the fluid being indicatedat X. It will be understood that the volume of the fluid may be variedbut that I prefer substantially to .1111 the interior of the plate,while leaving adequate space to take up the expansion of the fluid whenit freezes. The fluid not merely serves as a hold-over. but provides thenecessary moisture for maintaining a. heat transmitting film between theopposed outer side faces of the coil lengths i and the inner faces ofthe side walls l6 and I1. If the fluid is admitted through the connector3|,

-it is free to fill the interior of the plate. In order to permit theliquid to flow to the entire space within the plate. I may slightlyreduce the di ameter of the curved bent portions 20, at least locally.Or it may be convenient to provide an additional. inlet. not hereinshown, to assist in the rapid filling of the plate.

In the form of Fig. 6. I use a much smaller volume of fluid. illustratedat Y. The hold-over factor. in the form of Fig. 6, is omitted, butenough l quid is delivered to the interior of the plate to provide thenecessary moisture for maintaining the heat transmitting films betweenthe op osed faces of the coil lengths l5 and the side walls i6 and I1. I

It will be realized that, whereas, I have described and illustrated apractical and operative device, nevertheless many changes may be made inthe size, shape, number and disposition of parts without departing fromthe spirit of my inventlon.- I therefore wish my description anddrawings to be taken as in a broad sense illustrative or diagrammatic,rather than as limiting me to my precise showing.

For example, I may employ a single coil within the cold plate instead ofusing the two coils which I show connected in. parallel, as shown inFigure l. I may also employ any suitable means for spacing or supportingthe coils in a plate. I illustrate for example, the supports or spacersIn in Figure l which may be employed in any suitable size, shape,number, and location.

A convenient and valuable embodiment of my invention is a coil having aplurality of rectilinear tubes of rectangular cross section, the tubesbeing connected to form a continuous coil, but pre formed or separatelyformed connectors which may advantageously be non-rectangular, orcircular in internal cross section.

It will be understood, for example, that I may. within the scope of myinvention and within the terms of my claims, employ a unitary tubestructure in which a rectangular tube is actually bent, and I do notwish to limit myself either to the employment of separate connectingportions or to the specific form or contouring or curvature of theconnecting portions, since my invention includes any fluid conductiveconnection between adjacent rectilinear duct lengths.

The use and operation of the present invention are as follows:

The efilciency of the plate herein shown and claimed depends upon the:adequacy of the heat transfer between the coil, within which therefrigerant is evaporated, and the opposed side walls it and i! of theplate. Sufficient fluid is admitted to the interior of the plate topermit the building up of films. The area occupied by the films isextended by the employment of square tubing, involving a substantialincrease of direct heat transfer area, as contrasted to structures inwhich round or oval tubing is employed. The liquid. such as a eutectic.provides the necessary material for the films, whether only a smallvolume is admitted, as in Fig. 6, or whether a large volume is admitted.as in Fig. 2. In the form of Fig. 6. it may be desirable to agitate theplate. to obtain an initial distribution of the liquid. beforeexhausting the interior of the plate.

In both forms of plate the interior is sufficiently exhausted tomaintain a substantial atmospheric pressure against the side walls ofthe plate. The pressure differential may vary widely as desired.depending upon the size of the over-all area of the plate and on thegauge of sheet metal used for the plate side walls. It may, for example,vary within the range of 4 inches or less. of vacuum, to 20 inches ormore, of vacuum. The effect of atmospheric pressure against the sidewalls is to maintain a very close contact between the inner 'faces ofthe walls and the opposed side faces of the tubing. This pressuredifierential results in a heat transfer rate as good as those 'of themetal itself; and far better than the heat transfer conditlon existingwhere metals are welded, brazed, or soldered together. The procedure issimple, and easily and quickly carried out. The result is a cold platehaving very efficient heat transfer characteristics between therefrigerant in the interior of the coil. and the exterior of the plate.

An important function of the rectilinear tubes is to provide an internalreinforcement for the plates. The plates of the type herein shown arefrequently in use in freezing presses and are subjected to heavypressure in order to compact the substances undergoing freezing betweenadjacent plates. The provision of rectilinear tubes has the doublefunction, in a structural sense, of resisting inward pressure againstthe side of the plate, and of holding the outer surfaces of the oppositefaces or sides of the plate, to true and parallel planes. Thus when thecoil structure is positioned within the plate and the plate interior ispartly exhausted, the outer pressure of theatmosphere against the wallsof the plate maintains the plate as a strong structural element, havingsubstantially true planes at each side, the planes of the outer surfacesof the two sides of the plate being substantially parallel.

This application may be regarded as a continuation in part of co-pendingapplication 571,863 filed January 8, 1945.

g I claim:

1. In a vacuum plate adapted for use in refrigeration, and adapted toresist heavy pressures, a I

some for meintei a partial vac in the space within said walls and aboutsaid coil structure su ficient to maintain said walls y pressed against,end in intimate contact with, the opposed generally plane top encibottom surfaces oi the coil, seici perellei rectilinear duct lengthsbeing suificient in number e being sumciently closely spaced to term areinforcement for said housing wells, and to maintain the outer surfacesof said housing walls generally plane 2. The structure of claim iicharacterized by and including a, eutectic liquid positioned within saidplate in the space within said housing and exterior to said coiistructure.

3. The structure of claim 1 characterized by w RIEFERZENCES CREE Thefollowing references are of record in the s, time of such space.

w file of this patent:

UN STATES PATENTS Number

